GeneralPAC- Making power system intuitive

Resources Section

This video tutorial does not items in the resources section

Do you have a question? Click on the "Questions & Answers forum" and ask away!

This video was brought to you by, making power systems Intuitive, Open and Free for Everyone, Everywhere. Consider subscribing and supporting through This is a mechanism for you to support us financially so we can continue making high quality power system video tutorials. Our corporate sponsor for this topic is from Seattle, Washington. Contact them for industrial and commercial power system studies.

Principles of Symmetrical Components Part 1D.

In this part we're going to investigate the difference between a balanced set of three phasors versus the unbalanced set, and some of the terminologies involved describing the balanced set versus the unbalanced set, which spills into symmetrical components. Let's get started.

These are the two phasors that were presented in part 1C, and by inspection I can tell you that this is an ABC system and this is also an ABC system. And both systems are balanced. But, we're going to make this system unbalanced and see how the phasors change. To make this an unbalanced set all we need to do is just grab these phasors and make the angle between IA and IC different than 120 degrees, or the angle between IA and IB different from 120 degrees. So, we could just rotate this, and as you can see as we rotate it the angle changes. Now, because the angle between these two guys are not 120 degrees and the angle between these two guys are not 120 degrees, this becomes an unbalanced set.

Now, let's put it back to where it was before. What if the magnitude of IB suddenly shrunk? So, now, IB looks something like that. So, the angle between IB and IC, well, that's 120 degrees, and the angle between IB and IA, well, that's also 120 degrees. But, the magnitude of phasors B is not equal to the magnitude of phasors C, and IB is also not equal to the magnitude of IA. So, because the magnitude of IB changes, this becomes an unbalanced set.

So, let's make the unbalance a little bit more severe. This configuration is also an unbalanced set of phasors. We're now going to cover some of the terminology that are involved describing balanced and unbalanced set of phasors, and how it spills into symmetrical comport. So, this is the balanced set of three phasors, right? Well, in a lot of the books and papers that we read, a balanced set is also described as a symmetrical system. An unbalanced is also described as an unsymmetrical system. So, we have the symmetrical system here and then the unsymmetrical system there.

Now, sometimes when describing faults, now we're talking about faults, we're describing faults or short circuits, sometimes we use the term symmetrical faults versus unsymmetrical faults. Or, we have a balanced fault versus an unbalanced fault. Now, these terminologies would describe how the phasors would look like if we had a balanced fault, or a symmetrical fault, or, if we had an unbalanced or an unsymmetrical fault. So, if you had a balanced fault we could expect the phasors for a balanced fault to look something like this. But, if we had an unsymmetrical fault or an unbalanced fault, we would expect the phasors to be unbalanced or look something like this.

So, that concludes part 1D. Now, in part two we'll actually go into how these symmetrical components are defined and constructed. If you haven't subscribed already please do so by clicking on the button that's on the bottom right corner of the screen. Look at the bottom of the page for additional information and as always visit for more power systems video tutorials. Thank you.

Greetings from the GeneralPAC Team!

We make high-quality Power Systems Video Tutorials on complex topics that are free and open to everyone!  Thank you so much for supporting us through Patreon so can continue doing good and valuable work.

What is Patreon and why do we use it?

Patreon is a fantastic portal that allows our fans and community to make monthly contribution (like Netflix subscription) so we can continue creating high-quality power systems video tutorials. In return, you get access to incredible perks like voting on future topics, getting your questions answered, access to VIP Q/A webinars with the creators of GeneralPAC, and much more! We THANK YOU for supporting us

Why do we need your support?

An incredible amount of time and effort is needed to develop high-quality video tutorials. Each video (Part 1 for example) takes approximately 10 hours to complete which includes learning the concept ourselves, brainstorming creative ways to teach and explain the concepts, writing the script, audio recording, video recording, and editing. It's no wonder why Hundreds-of-Thousands of people have watched, liked, subscribed, and left positive comments on Youtube channel. Your support truly makes all the difference.

Become a patron today!